1. Field of the Invention
The present invention relates generally to encoding digital data in printed media or materials, and more particularly, to trading cards and other printed media products that include graphics and text that is visible and understandable to a human user and that further include a data file including data, such as multi-media data, that is dot encoded. The dots are colored, such as cyan, yellow, and magenta, and are printed over the top of each other with each particular color representing a layer or plane of data, i.e., a subset of the encoded data file. A scanner with a decoding module can resolve each color separately, decode the set of dots in that layer or plane, and then combine the decoded data files into a single data file that can be further processed by a user application file, such as an audio or video output application.
2. Relevant Background
A recent and growing trend is the inclusion of binary or digital data on numerous products and objects, such as identification cards, grocery and other retail products, driver's licenses, and myriad other goods. Often, the data is encoded and printed in a symbol, such as a bar code, that can be readily printed with existing printer technology and then optically scanned by a fixed or hand held scanner that decodes the symbol to obtain the digital data. In other words, digital or binary data can be provided on a printed substrate or media rather than just on magnetic media such as floppy and hard disks and optical media such as compact disks. While bar codes contain a relatively small amount of information, encoding methods have been, and are continuing to be, developed that allow more and more information to be placed on printed substrates and products. As printing and scanning technologies and densities increase, there will be a significant increase in the demand for data files on a diverse range of printed media and that there will be a demand for the amount of information provided in such files to be much larger.
An example of relatively simple encoded data file is a barcode (or uniform product code (UPC) symbol) found on almost all retail products. Barcodes have been available for encoding data for over thirty years. A traditional one-dimensional bar code is a machine-readable code consisting of a series of bars and spaces printed in different ratios. Bar code symbologies are essentially alphabets in which different widths of bars and spaces are combined to form characters to encode data. However, traditional barcodes encode at most a couple of dozen digits. Rather than providing a complete set of useful information, the standard bar code when decoded by an optical scanner provides a key to a database containing detailed information that must be accessed on an ongoing basis.
Two dimensional (“2D”) barcodes were developed as one method of encoding more useful data in a printed label or symbol. 2D barcodes can encode more information in less space than traditional barcodes by storing data along the length and the height of the barcode, i.e., in two directions or dimensions. In 2D barcodes, because the vertical redundancy is gone, techniques must be used to prevent misreads. Most two dimensional codes use check words to insure accurate reading. One well-known 2D barcode is the PDF417 barcode, which does not require an external database as the symbol includes all the related information in a portable data file. The widespread use of bar codes has resulted in the technology to create one-dimensional and 2β barcodes being well-developed and relatively inexpensive.
More recently, color has been used to allow data to be encoded. For example, colored bar arrays bearing encoded information are used for color-coding electrical and electronic resistors. In another example of the use of color in encoding data, U.S. Pat. No. 5,369,261 to Shamir describes a technique of representing encoded information in terms of a matrix of bar-like or dot-like regions that are encoded by variables of both color and intensity. The system provides color coded dots, bars or regions arranged to form super pixels in which each super pixel is defined by a series of minute areas, each having a distinct color within or without the visible spectrum, with each minute area having a predetermined intensity or shade of color much like conventional shades of gray. The use of color has provided some useful advances in encoding data but often has been utilized in a manner that significantly increases costs or adds to the complexity of the printing or the scanning equipment.
There remains a need for methods of encoding high-density, multi-media data on printed media or substrates. Preferably, such a method would be useful for encoding data in a manner that allows existing printer and scanner technology to be utilized but that provides a significant increase over existing encoding techniques in the volume of data that can be stored in the same amount of space. By using at existing printer and scanner technology, costs of implementing the data-encoding and decoding methods can be controlled.